Black bars are determined by lines of pixels. Steps include: for each line (or subset), determining standard deviation (or product value) and a difference value, product value being proportional to M·σ, where M is pixel values mean for the line, σ standard deviation of pixel values for the line, and the difference value a difference between the standard deviation (or product) value for the line and the standard deviation (or product) value for one of the lines adjacent to the line, and determining whether any of the lines satisfies the criterion that the difference value for the line exceeds a threshold but the difference value for each other one of the lines to be displayed nearer to a first edge of the image than is the line does not exceed the threshold. Other aspects are a system or device configured (e.g., programmed) to perform any embodiment of the method.